Earnings per share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Numerator:
Net income attributable to Stewart	$ 61,660	$ 94,819	$ 119,557	$ 149,055
Denominator (000):
Basic average shares outstanding (in shares)	27,018	26,798	26,989	26,767
Diluted average shares outstanding (in shares)	27,293	27,123	27,377	27,038
Basic earnings per share attributable to Stewart (in usd per share)	$ 2.28	$ 3.54	$ 4.43	$ 5.57
Diluted earnings per share attributable to Stewart (in usd per share)	$ 2.26	$ 3.50	$ 4.37	$ 5.51
Stock options
Denominator (000):
Average number of dilutive shares relating to grants of restricted shares and units (in shares)	154	189	226	154
Restricted stock and restricted stock units
Denominator (000):
Average number of dilutive shares relating to grants of restricted shares and units (in shares)	121	136	162	117